Special Episode of Hidamari Sketch x365 Announced [Update]

At an event "Chou Hidamatsuri Z" held on April 5th, special episode(s) of "Hidamari Sketch x 365" was announced to be released. The release date and the number of episodes haven't been given yet.

Source: MOONPHASE
Source: Hidamari Sketch official website

Update
According to the poster notice, the special episodes will be aired on October 17th and 24th.

Source: Scan of the poster